Uranyl Research Articles

Coordination interaction based two-dimensional photonic crystal polyacrylic acid hydrogel material for sensitive and visual detection of uranyl ion in water

Coordination interaction based two-dimensional photonic crystal polyacrylic acid hydrogel material for sensitive and visual detection of uranyl ion in water

All‐in‐One: Photo‐Responsive Lanthanide‐Organic Framework for Simultaneous Sensing, Adsorption, and Photocatalytic Reduction of Uranium

AbstractThe selective removal and immobilization of uranyl ions from aqueous solutions is essential for the sustainable development of nuclear energy. Herein, a robust lanthanide‐organic framework material (IHEP‐24) is developed for simultaneous fluorescence sensing, selective adsorption, and photocatalytic reduction of uranium, integrating three different functions in one material. The confined space formed by the coordination assembly of viologen derivative ligands and metal‐oxygen clusters can act as precise recognition sites for uranyl, allowing IHEP‐24 to efficiently detect and capture uranyl ions. In addition, the presence of a viologen‐based radical ligand enables IHEP‐24 to a further photocatalytic reduction of the adsorbed uranyl to amorphous UO2. The mechanisms of adsorption and photocatalysis are revealed by batch experiments, photoelectrochemical characterizations, and theoretical calculations. This study provides a reference for the construction of robust multi‐functional MOF materials and also provides support for the deep removal and immobilization of radionuclides from aqueous solution.

New insights into hydration shells in boosting marine uranium adsorption kinetics

Identifying mass transfer is essential for boosting adsorption kinetics. The internal and external diffusions serve as rate-limiting steps. The liquid film diffusion is commonly identified as external diffusion, while the mass diffusion across the ubiquitous hydration shell is generally ignored. Charged functional groups can bind water molecules strongly via electrostatically induced hydration. Herein, three representative polar polymers, including cation polymer (PDMAPAA), anion polymer (PSS) and zwitterion polymer (PSBMA), are crosslinked with polyamioxime (PAO) to synthesize radially aligned PAO-PDMAPAA, PAO-PSS, PAO-PSBMA, respectively, by a bidirectional freeze-casting. We focus on the effect of hydration structure and hydration dynamics on marine uranium extraction performance. It is found that the external diffusion in PAO-polar polymer adsorbents can be facilitated due to fast water exchange in dynamic hydration shell, leading to a reduced adsorption equilibrium time compared with the pristine PAO. However, the high hydration degree causes strong viscous shear and high dehydration barrier, which impede the complexation of UO22+ with binding sites of PAO. Although the hydration degree follows the order of PAO-PSBMA > PAO-PDMAPAA > PAO-PSS, PAO-PDMAPAA delivers the shortest equilibrium time required. In addition, the increasing temperature would weaken viscous shear in static hydration shell, which equivalently reduces the apparent friction of hydrated uranyl ions. Consequently, light-irradiated GO@PAO-PDMAPAA adsorbent, in which GO acts as a photothermal mediator, yields a shorter equilibrium time (∼18 days) than PAO-PDMAPAA together with a high uranium adsorption capacity of 12.24 mg-U/g-Ads in natural seawater. These findings provide valuable guidance for enhancing uranium adsorption kinetics associated with hydration shell.

A Phosphorylated Dendrimer-Supported Biomass-Derived Magnetic Nanoparticle Adsorbent for Efficient Uranium Removal.

A novel biomass-based magnetic nanoparticle (Fe3O4-P-CMC/PAMAM) was synthesized by crosslinking carboxymethyl chitosan (CMC) and poly(amidoamine) (PAMAM), followed by phosphorylation with the incorporation of magnetic ferric oxide nanoparticles. The characterization results verified the successful functionalization and structural integrity of the adsorbents with a surface area of ca. 43 m2/g. Batch adsorption experiments revealed that the adsorbent exhibited a maximum adsorption capacity of 1513.47 mg·g-1 for U(VI) at pH 5.5 and 298.15 K, with Fe3O4-P-CMC/G1.5-2 showing the highest affinity among the series. The adsorption kinetics adhered to a pseudo-second-order model (R2 = 0.99, qe,exp = 463.81 mg·g-1, k2 = 2.15×10-2 g·mg-1·min-1), indicating a chemically driven process. Thermodynamic analysis suggested that the adsorption was endothermic and spontaneous (ΔH° = 14.71 kJ·mol-1, ΔG° = -50.63 kJ·mol-1, 298. 15 K), with increasing adsorption capacity at higher temperatures. The adsorbent demonstrated significant selectivity for U(VI) in the presence of competing cations, with Fe3O4-P-CMC/G1.5-2 showing a high selectivity coefficient. The performed desorption and reusability tests indicated that the adsorbent could be effectively regenerated using 1M HCl, maintaining its adsorption capacity after five cycles. XPS analysis highlighted the role of phosphonate and amino groups in the complexation with uranyl ions, and validated the existence of bimodal U4f peaks at 380.1 eV and 390.1 eV belonging to U 4f7/2 and U 4f5/2. The results of this study underscore the promise of the developed adsorbent as an effective and selective material for the treatment of uranium-contaminated wastewater.

Surface structural transformation and adsorption performance of poly(triazine imide)

Abstract Poly(triazine imide) synthesized by the molten salt route with incorporation of Li+ and Cl‒ ions (PTI/Li+Cl−) was prepared by rational controlling of the washing extent. The surface transformation of the phase-pure PTI framework incurred by thorough washing has been confirmed by a systematic analysis based on x-ray diffraction, Ultraviolet Raman, atomic force microscope, and x-ray photoelectron spectroscopy measurements. Uranyl ion adsorption experiments further support the surface structural transformation from triazine-unit PTI to heptazine-based graphitic carbon nitride. Efforts on the exploration of PTI material application should be mainly directed toward the waterless fields to give good repeatability.

Investigations on the Equilibrium, Kinetics and Thermodynamics of Anionic Polyacrylamide-Based Monolith Adsorption of Uranium (VI) From Aqueous Solution

Our previous work discussed synthesizing and characterizing a macroporous anionic polyacrylamide monolith as a new adsorbent. This monolith showed the potential removal of heavy metals and organic dye molecules in aqueous solutions. In this work, we continue our work and study the effectiveness of the synthesized monoliths in removing uranyl ions (UO22+) from aqueous solutions. Our investigation conclusively determined the impact of pH, contact time, monolith dosage, initial metal concentration and temperature on removing uranyl ions. Several isotherm models, including the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich models, were employed to analyze the adsorption data; the Freundlich and Langmuir models were the most suitable for describing the equilibrium data. According to the Langmuir model, the monolith has an adsorption capacity of 111 mg/g of uranyl ions at 25 °C. The pseudo-second-order kinetic model was suitable for describing the uranyl ion adsorption onto the synthesized monolith with an R2 coefficient ³ 0.999. The thermodynamic studies showed that uranyl ions adsorb onto the monolith spontaneously and endothermically.

Facile and scalable synthesis of functionalized hierarchical porous polymers for efficient uranium adsorption

Efficient uranium capture from wastewater holds great importance for the environmental remediation and sustainable development of nuclear energy, but it is a tremendous challenge. Herein, a facile and scalable approach is reported to fabricate functionalized hierarchical porous polymers (PPN-3) decorated with high density of phosphate groups for uranium adsorption. The as-constructed hierarchical porous structure could allow rapid diffusion of uranyl ions, while abundant phosphate groups that serve as adsorption sites could provide the high affinity for uranyl. Consequently, PPN-3 shows a high uranium adsorption uptake of 923.06 mg g−1 and reaches adsorption equilibrium within simply 10 min in uranium-spiked aqueous solution. Moreover, PPN-3 affords selective adsorption of uranyl over multiple metal ions and possesses a rapid and high removal rate of U(VI) in real water systems. Furthermore, this study offers direct polymerization strategy for the cost-effective fabrication of phosphate-functionalized porous organic polymers, which may provide promising application potential for uranium extraction.

Enhanced Uranium Extraction via Charge Dynamics and Interfacial Polarization in MoS2/GO Heterojunction Electrodes.

The removal of uranyl ions (UO2 2+) from water is challenging due to their chemical stability, low concentrations, complex water matrix, and technical limitations in extraction and separation. Herein, a novel molybdenum disulfide/graphene oxide heterojunction (MoS2/GO-H) is developed, serving as an effective electrode for capacitive deionization (CDI). By combining the inherent advantages of electroadsorption and electrocatalysis, an innovative electroadsorption-electrocatalysis system (EES) strategy is introduced. This system utilizes interface polarization at the MoS2 and GO interface, creating an additional electric field that significantly influences carrier behavior. The MoS2/GO-H electrode, with its extraordinary adsorption capacity of 805.57mgg-1 under optimal conditions, effectively treated uranium-laden wastewater from a mine, achieving over 90% removal efficiency despite the presence of numerous competing ions at concentrations significantly higher than UO2 2+. Employing density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, it is found that the MoS2/GO-H total charge density at the Fermi level, enhanced by interfacial polarization, surpasses that of separate MoS2 and GO, markedly boosting conductivity and electrocatalytic effectiveness.

High-efficiency and economical uranium extraction from seawater with easily prepared supramolecular complexes

Developing effective adsorbents for uranium extraction from natural seawater is strategically significant for the sustainable fuel supply of nuclear energy. Herein, stable and low-cost supramolecular complexes (PA-bPEI complexes) were facilely constructed through the assembly of phytic acid and hyperbranched polyethyleneimine based on the multiple modes of electrostatic interaction and hydrogen bonding. The PA-bPEI complexes exhibited not only high uptake (841.7 mg g−1) and selectivity (uranium/vanadium selectivity = 84.1) toward uranium but also good antibacterial ability against biofouling. Mechanism analysis revealed that phosphate chelating groups and amine assistant groups coordinated the uranyl ions together with a high affinity. To be more suitable for practical applications, powdery PA-bPEI complexes were compounded with sodium alginate to fabricate various macroscopic adsorbents with engineered forms, which achieved an extraction capacity of 9.0 mg g−1 in natural seawater after 50 days of testing. Impressively, the estimated economic cost of the macroscopic adsorbent for uranium extraction from seawater ($96.5 ∼ 138.1 kg−1 uranium) was lower than that of all currently available uranium adsorbents. Due to their good uranium extraction performance and low economic cost, supramolecular complex-based adsorbents show great potential for industrial uranium extraction from seawater.

Advanced Uranium Removal with Pure, Nonfluorinated Ionic Liquids: Fine-Tuning Hydrophilic and Hydrophobic Properties for Enhanced Selectivity.

Ionic liquids (ILs) have significant potential for eco-friendly extraction of uranium from aqueous solutions, which is critical for nuclear technology, fuel cycle management, and environmental protection. This study examines the impact of the adjustable hydrophobic/hydrophilic properties of ILs on the removal of uranium(VI) (UO22+) from aqueous solutions utilizing both a novel hydrophilic IL (1-butoxyethyl-1-methylmorpholinium butoxyethylphosphite - Mor1-2O4-BOEP) and 1-heptyl-1-methylmorpholinium heptylphosphite (Mor1-7-HP) as an example of a hydrophobic IL with a similar structure. The transfer mechanism of uranyl ions from water to organic or solid phases closely depends on the physicochemical properties of ILs, especially their hydrophobicity. The hydrophobic Mor1-7-HP extracts uranyl via neutral complex formation as UO2(NO3)2-(Mor1-7-HP)2. Conversely, hydrophilic Mor1-2O4-BOEP induced selective precipitation as UO2(NO3)-(BOEP), transferring uranyl to the solid phase. Optimization of the working parameters, in terms of acidity of the aqueous solution and amount of ILs used, allowed the extraction of over 98% of U(VI). The stoichiometry of the organic complex and the precipitate was determined using physicochemical techniques. These tunable H-phosphonate-based ILs have advantages over traditional solvent extraction and conventional ILs, allowing easier handling, improved selectivity, and lower environmental impact. This work advances uranium separation techniques with applications in hydrometallurgy, particularly in the treatment of wastewater and radioactive waste for sustainable uranium recovery.

Robust advantage of MXene/g-C3N4 loaded on Fe2WO6/BiIO4 nano-platform for chemo-peroxidase colorimetric detection of uranyl ions, antifungal properties, photocatalytic degradation of p-chlorophenol, and eco-toxicity studies

In this study, we have designed a nanocomposites based on MXene/g-C3N4 (MX/CN) loaded on Fe2WO6/BiIO4 (FWO/BIO) for different applications. The nanocomposites were identified by using the structural and morphological studies including XRD, FESEM, EDS, DLS, TGA, BET, UV–vis, XPS techniques. The average sizes of BIO, FWO/BIO, and MX/CN/FWO/BIO were 44, 46, and 58 nm, respectively. The synthesized MX/CN/FWO/BIO nanocomposites was utilized for the peroxidase colorimetric identification of uranyl ions (UO22+) with the excellent selectivity and sensitivity properties (LOD: 3.21 nM). The antifungal efficiency of the as-fabricated nanomaterials was investigated and the inhibition zone at high concentration 2.5 mg/mL of MX/CN/FWO/BIO nanocomposites were 19.74, 17.91, 24.25, and 21.32 mm against Aspergillus spp., Penicillum spp., Candida spp. and Fusarium spp., respectively. The MX/CN/FWO/BIO nanocomposites was utilized in photocatalysis process for decomposition of p-chlorophenol under visible light lamp. The findings showed that the MX/CN/FWO/BIO nanocomposites can be degrade p-chlorophenol (100.0 %) under visible light irradiation (80 min). The photocatalytic response was decreased about 2 % after 5th cycle times, and showed the best stability of the MX/CN/FWO/BIO nanocomposites. The quenching test shows the mechanism of p-chlorophenol degradation was conducted by •O2−, and •OH species. Additionally, the ecological structure activity relationships ECOSAR software was utilized to evaluate the toxicity of the p-chlorophenol and the intermediates produced. This work can lead for manufacturing innovation in near future.

Water-soluble, SDS-functionalized CdSe/CdS/ZnS quantum dots for uranium detection in aqueous environments

Water-soluble fluorescent probes for conveniently and rapidly monitoring the hazardous uranyl ions (UO22+) in nuclear wastewater are crucial for public nuclear security. Herein, we demonstrated a water-soluble CdSe/CdS/ZnS QDs probe by substituting hydrophilic dodecyl sodium sulfate (SDS) ligands for the original hydrophobic oleic acid ligands toward the rapid and accurate detection of trace UO22+ in aqueous environments. From this simple ligand exchange mothed, the as-prepared QDs probe exhibited a narrow full width at half maximum (FWHM) of 53 nm with an emission peak at 666 nm. Benefiting from dynamic and static fluorescence quenching interaction, this probe represented a high sensitivity (a detect limit of 15.4 nM), a high selectivity with comparison of presettable eight metal ions), a high environmental stability (a recovery rate of 81–94 %) and a rapid inspection ability (on the order of a few minutes). Therefore, this work provided a new approach for the determination of UO22+ in aqueous environments and then for the assurance of public nuclear security.

Study on Natural Diatomite as an Adsorbent for Uranyl (VI) ions, Using Spectrophotometric Method

This work is based on the investigation of uranyl (VI) ion adsorption onto natural diatomite using batch sorption method under different parameters such as pH, initial ion concentration, adsorbent amount and effect of sulfate ion as a foreign ion. 8-hydroxyquinoline is used as a chromogen forming a pale-yellow complex with ions in chloroform, the absorbance was measured spectrophotometrically at λmax 460 nm, obtaining a linear calibration curve with R2=0.998, LOD=3.03 mg/L and LOQ=9.21 mg/L. Prior to the implementation of the batch experiment, the morphology and composition of diatomite was confirmed using XRF (Bruker S8 Tiger), XRD (Bruker D5005), FTIR (Bruker Vector 22), and SEM (JEOL JSM-5610 LV) techniques. From spectrophotometric analysis, the results showed that the maximum uranyl ion adsorption distribution coefficient reached at the initial concentration of 50ppm, pH 4.5, contact time 5hrs and adsorption dosage of 2 g/L. There was no significant effect of sulfate ion on the adsorption affinity. Adsorption isotherm was studied by Langmuir which was favourable model fitting with R2=0.996 and maximum adsorption capacity of 16mg/g, and separation factor RL = 0.0122. Freundlich isotherm model also applied for the same data and give a very straight line with R2= 1.00 and maximum adsorption capacity of 200 mg/g. Temkin model was less fit and gave a negative isotherm curve with R2= 0.78, KT= 0.9405 L/g, bT= 24.724 J/mol. Langmuir and Freundlich isotherms gave exothermic adsorption while Temkin gave an endothermic one.

Constructing amidoxime adsorption sites on the core-shell structured natural silk protein for uranium capture

Amidoxime-based fiber adsorbents hold significant promise for uranium extraction. However, a notable issue is that these adsorbents primarily originate from synthetic polymer materials, which, aside from providing good mechanical support, have no other functions. In recent study, we shifted our focus to silk fiber (SF), a natural protein fiber known for its unique core-shell structure and rich amino acids. The shell layer, due to its abundant functional groups, makes it easily modifiable, while the core layer provides excellent mechanical strength. Leveraging these inherent properties, an amidoxime-based fiber adsorbent was developed. This adsorbent utilizes amino and carboxyl groups for enhanced performance synergistically. This method involves establishing uranium affinity sites on the outer sericin layer of SF via chemical initiation of graft polymerization (CIGP) and amidoximation (SF-g-PAO). The water absorption ratio of SF-g-PAO is as high as 601.16 % (DG = 97.17 %). Besides, SF-g-PAO demonstrates an exceptional adsorption capacity of 15.69 mg/g in simulated seawater, achieving a remarkable removal rate of uranyl ions at 95.06 %. It can withstand a minimum of five adsorption-elution cycles. Over a 4-week period in natural seawater, SF-g-PAO displayed an adsorption capacity of 4.95 mg/g. Furthermore, SF-g-PAO also exhibits impressive uranium removal efficiency in real nuclear wastewater, with a removal rate of 63 % in just 15 min and a final removal rate of 90 %. It is hoped that this SF-g-PAO, prepared through this straightforward method and characterized by the synergistic action of amino and carboxyl groups, can offer innovative insights into the development of uranium extraction adsorbents.

Carboxymethylcellulose-based zwitterionic cryogels for efficient U(VI) extraction from water

Carboxymethylcellulose-based zwitterionic cryogels (AO-PAM/CMC) with a supermacroporous pore structure were prepared through cryo-polymerization and post-modification strategies. The hydrogel exhibited a supermacroporous structure, excellent hydrophilicity, superior mechanical properties, and resistance to biological contamination. Through a comprehensive investigation of the U(VI) adsorption process, it was observed that the AO-PAM/CMC hydrogel was predominantly characterized by chemisorption, wherein uranyl ions were adsorbed on the surface in the form of a monolayer. Under the conditions of 45 °C and pH = 5.0, the hydrogel demonstrated remarkable adsorption performance, with the maximum adsorption capacity reaching 1223.6 mg∙g−1, showcasing a high degree of selectivity for U(VI). In real seawater, the hydrogel's adsorption capacity for uranium reached 12.95 mg∙g−1 after 25 days of exposure, with the adsorption equilibrium being essentially reached in about 10 days. The adsorption mechanism of U(VI) by the hydrogel was confirmed through XPS spectroscopy and DFT calculations. The synergistic interplay between guanidino and zwitterionic moieties within the AO-PAM/CMC hydrogel enhanced U(VI) adsorption capacity and facilitated rapid uranium extraction from seawater. (UES). Therefore, the AO-PAM/CMC hydrogel presents a novel solution to address the inefficiencies of existing technologies for uranium extraction from seawater, contributing an innovative approach to the sustain-able development of nuclear energy.

Decoration of phosphoric acid groups onto Ti3C2Tx MXene for enhanced uranium removal

The construction of novel MXene-based composites with superb abilities through functionalization is an effective strategy to enhance the potential of this emerging inorganic lamellar material for environmental adsorption applications. The present work systematically investigated the adsorption performance of Ti3C2Tx MXene modified with phosphate functional groups that facilitate the capture of uranyl ions. After introducing phosphate groups via a two-step modification of 3-aminopropyltriethoxysilane (APTES) and phytic acid (PA), the synthesized Ti3C2-APTES-PA is significantly superior to pristine Ti3C2Tx nanosheets in terms of adsorption capacity, adsorption selectivity and reusability for uranium. The maximum uptake capacity of Ti3C2-APTES-PA at pH = 5 reaches 323 mg/g, which is 2.5 times higher than that of unmodified MXene. Furthermore, the large selectivity coefficient (SU/M > 16.2) declares that Ti3C2-APTES-PA preferentially adsorbs uranium among substantial competing ions. Ti3C2-APTES-PA also shows good cycling performance that its adsorption capacity remained 92.3 % after 6 cycles. When it comes to treating simulated uranium tailings pond leachate and radioactive wastewater from mines, high U(VI) removal rates of 88.9 % and 96.8 % can be achieved by our ternary composite at a dosage of 0.05 g/L. The underlying adsorption mechanism was unraveled by spectroscopic analysis to be the formation of coordination complexes of uranyl ions with phosphate groups on PA and hydroxyl groups on Ti3C2Tx substrate, as well as the reduction of a small amount of adsorbed U(VI) to U(IV) by MXene. The overall results imply that Ti3C2-APTES-PA is an effective uranium chelating scavenger for the treatment of environmental radioactive wastewater.

The efficient uptake of uranium by amine-functionalized β-cyclodextrin supported fly ash composite from polluted water

A novel polyethyleneimine/polydopamine-functionalized β-cyclodextrin supported fly ash adsorbent (PEI/PDA/β-CD/FA) had been synthesized to uptake uranium from polluted water. At pH = 5.0 and T = 298 K, the uranium uptake efficiency and capacity of PEI/PDA/β-CD/FA reached to 98.7 % and 622.8 mg/g, respectively, which were much higher than those of FA (71.4 % and 206.7 mg/g).The excellent uranium uptake properties of PEI/PDA/β-CD/FA could be explained by three points: (1) using β-CD as a supporting material could effectively avoid the aggregation of FA and improve the hydrophily of FA; (2) the unique cavity structure of β-CD could form chelates with uranyl ions; (3) the formation of PEI/PDA co-deposition coating on FA further enhanced the affinity of FA to UO22+. With the presence of interfering ions, the uptake efficiency of PEI/PDA/β-CD/FA for uranium was still up to 94.5 % after five cycles, indicating the high selectively and recoverability of PEI/PDA/β-CD/FA. In terms of the results of characterizations, uranium was captured by PEI/PDA/β-CD/FA via electrostatic attraction, hydrogen bond, coordination and complexation. To sum up, PEI/PDA/β-CD/FA was expected to be used for actual sewage treatment owing to its excellent uranium uptake efficiency/capacity, selectivity, cycle stability and feasibility of actual application.

Artemisinin gum reinforced porous amidoxime aerogel with high efficiency adsorption for uranium extraction from seawater

The extraction of uranium resources from the ocean is of great importance in energy exploration. This work reported a polysaccharide composite aerogel to adsorb uranium from the ocean, a facile freeze-drying strategy was explored to create a physically crosslinked artemisia sphaerocephala krasch gum (ASKG)-poly(amidoxime) (PAO) aerogel (ASKG@PAO). Due to the excellent hydrophilicity and swelling properties of artemisia spherecephala krasch gum, the ASKG@PAO can quickly and stably adsorb uranyl ions in the ocean. The batch adsorption test results show ASKG@PAO (mASKG: mPAO = 1:1) has an excellent uranium removal rate (93.92 %) and a high uranium adsorption capacity (341.11 mg/g). Desorption kinetic experiments show that the ASKG@PAO can desorb 90 % of the uranyl ions within 10 min and retain a removal rate of 87.3 % after five adsorption–desorption cycles. In addition, ASKG@PAO has excellent selectivity for uranyl ions. Consequently, ASKG@PAO aerogel has significant potential for extracting marine uranium resources.

Interface coupling induced built-in electric fields accelerate electro-assisted uranium extraction over Co3O4@FeOx nanosheet arrays

Revealing the nature of enhanced electro-assisted uranium extraction activity by hetero-interface and M-O-H coordination bonds is an important and challenging task. Hence, Co3O4@FeOx nanosheet arrays with abundant M-O-H coordination bonds is fabricated as a binder-free and self-supporting electrocatalyst for electro-assisted uranium extraction from fluorine-containing uranium wastewater. As revealed by self-consistent energy band calculations and in-situ Kelvin Probe Force Microscopy (KPFM) analysis, the p-n heterojunction formed by Co3O4@FeOx provides a well-designed built-in electric field (BIEF), triggering the interfacial accumulation of uranium and accelerating the electro reduction kinetics of uranium. Consequently, Co3O4@FeOx shows remarkable U(VI) extraction ability (>95 %) in fluorine-containing uranium wastewater. By virtue of the XAFS spectra, free uranyl ions are captured by M-O-H on Co3O4@FeOx to form a sturdy 2 Oax-1 U-3 Oeq configuration, confirming the electrically driven separation of uranium and fluorine. Furthermore, DFT calculation indicates that the existent of M-O-H enhances the adsorption energy of uranium species, thus promoting uranium extraction efficiency.

Photouranium-Catalyzed C-F Activation Hydroxylation via Water Splitting.

The C-F bond is the strongest covalent single bond (126 kcal/mol) in carbon-centered bonds, in which the highest electronegativity of fluorine (χ = 4) gives rise to the shortest bond length (1.38 Å) and the smallest van der Waals radius (rw = 1.47 Å), resulting in enormous challenges for activation and transformation. Herein, C-F conversion was realized via photouranium-catalyzed hydroxylation of unactivated aryl fluorides using water as a hydroxyl source to deliver multifunctional phenols under ambient conditions. The activation featured cascade sequences of single electron transfer (SET)/hydrogen atom transfer (HAT)/oxygen atom transfer (OAT), highly integrated from the excited uranyl cation. The *UO22+ prompted water splitting under mild photoexcitation, caging the active oxygen in a peroxo-bridged manner for the critical OAT process and releasing hydrogen via the HAT process.